|From:||Ranga Radhakrishnan <r.radhakrishnan@...652...>|
|Date:||Wed, 21 Jun 2017 11:54:02 +0100|
Hi,I think that I have a few issues with the lubricate/poly implementation in LAMMPS based on my reading of Microhydrodynamics book by Kim and Karilla .
1) The gap-distance (h_sep) between the particles should be scaled by (radi+radj)/2 and not as radi, where radi, radj are the radii of the two particles.
2) The first term in the squeeze force seems to be missing a prefactor of 2.3) \omega^\infty seems to have the wrong units. It is because "h_rate" has the units of length.
4) The pump term is also incorrect for particles of different sizes. Briefly, specific cases of calculation of torques in Ref.  cannot be used to write down a generalized version.
Please look at the attached pdf for a more detailed explanation on why I raised these concerns, and how to implement a "corrected" lubrication force if you agree with my concerns. Just to be clear, I have looked at previous messages in the mailing list before I send this message, and I don't think any of the previous messages have answered my concerns.
Description: Adobe PDF document